Do not support universal wheels
My comment from github for context:
```
As I am not quite sure about the impact of the C-code and the overall maintenance and distribution burden, I would rather remove it entirely.
In the current implementation using setup.py it would try to build the code, and just keep going on failure. Something like that I would love to have for the wheel as well.
Alternatively, maybe it's possible to keep supporting the setup.py for those who want to have a chance to improved performance, and those who use wheels will still get the python-only version.
I will just merge the commit for now, but do indeed hope there is a way to make this work.
```